Inhalers and atomizers are now commonly used primarily to deliver various liquid medicaments via the patient's or user's nose or mouth. As used herein, “medicament” includes any powder or liquid medicament, drug or vaccine which may be administered from a respiratory delivery device through the user's nose or mouth, sometimes referred to herein as a medicament respiratory delivery device. More recently, the prior art has proposed unit dose disposable powder medicament delivery devices, such as disclosed in U.S. Pat. No. 5,215,221, wherein a predetermined quantity or unit dose of a powder medicament is sealed in a reservoir formed between opposed thermoplastic sheets and expressed or delivered by application of manual force to a thermoformed blister which, upon actuation, breaks a burstable seal between the sheets at the entrance to the reservoir and fluidizes the powder medicament in the reservoir through a delivery tube. The delivery tube is cut prior to use.
There are several considerations affecting the design and efficacy of medicament respiratory delivery devices. First, it is important to ensure that a predetermined quantity or dose of medicament is consistently delivered to the user with each application. Second, because respiratory therapy often requires numerous applications, the cost of providing the dosage should also be considered. That is, it is desirable that the medicament respiratory delivery device consistently express substantially all of the medicament to the user and that the delivery device is not susceptible to user error in operation. Third, it is important that the medicament be properly disbursed or entrained in the conveying fluid. Further considerations include operating complexity, cost of the device, portability and size of the delivery device.
The embodiments of the medicament respiratory delivery devices and medicament cartridge of this invention provides a reproducible, high level of clearance of medicament or emitted dose from the cartridge upon actuation with modest gas pressure.